css-extractor.js

function css(tags, ...attrs) {
  const value = style(tags, ...attrs)
  const node = document.createElement('style')
  node.id = 'insertedStyle'
  node.appendChild(document.createTextNode(value))
  const sheet = document.getElementById('insertedStyle')
  if (sheet) {
    sheet.disabled = true
    sheet.parentNode.removeChild(sheet)
  }
  document.head.appendChild(node)

  function style(tags, ...attrs) {
    if (tags.length === 0) return ''
    let result = ' ' + tags[0]
    for (let i = 0; i < attrs.length; i++) {
      result += attrs[i]
      result += tags[i + 1]
    }
    return result
  }
}